Carbonatation Influence on Fly Ash and Portland Cement Mortars

Abstract

THE INFLUENCE OF CARBONATION ON MORTARS CONTAINING 25% OF FLY ASH INSTEAD OF THE CEMENTITIOUS MATERIALS WAS STUDIED. MORTAR CYLINDER SPECIMENS WERE FABRICATED FOR 4 DIFFERENT W/C RATIOS: 0.35, 0.45, 0.55 AND 0.65. MORTARS WITH AND WITHOUT FLY ASH WERE SUBJECTED TO AN ACCELERATED CARBONATION PROCESS. VOLUMETRIC WEIGHT, WATER ABSORPTION, COMPRESSIVE STRENGTH, WATER PERMEABILITY, PH AND MERCURY INTRUSION POROSIMETRY OF THE MORTAR SPECIMENS WERE DETERMINED. DUE TO THE FLY ASH POZZOLANIC POTENTIAL, FOR ALL W/C RATIOS, RESULTS OF THE COMPRESSIVE STRENGTH TESTS AT 28 DAYS OF THE MORTARS WITH AND WIT HOUT FLY ASH WERE SIMILAR. MORTARS WITH FLY ASH PRESENTED SIMILAR WATER PERMEABILITY AS MORTARS WITHOUT FLY ASH. PH RESULTS SHOWED THAT ALKALINITY REDUCTION IS LOWER IN MORTARS WITH FLY ASH COMPARED TO THOSE CONTAINING CEMENT ONLY. IN ALL THE MORTARS, THE POROSIMETRIC ANALYSIS INDICATED THAT POROSITY IS REDUCED DUE TO CARBONATION. FURT HER MORE, IT IS SHOWED THE PREDOMINANCE OF THE MACRO AND MESOPORES.